<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        // 变量
        let num1 = 100;
        let str1 = "hello";
        let bool = true;
        let num2 = 9.9;
        // 函数
        function showInfo(){
            let num3 = 999;
            console.log(num3);
        }
        // showInfo();
        // console.log(num3);

        for(var i = 0;i < 5;i++){
            console.log(i);
        }
        console.log(i);
    </script>
</body>
</html>